﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Security.Cryptography;
using System.Text;
using System.IO;

/// <summary>
/// Security 网址参数加密
/// </summary>
public class Security
{
	public Security()
	{
		//
		// TODO: 在此处添加构造函数逻辑
		//
	}
    string _QueryStringKey = "abcdefgh"; //URL传输参数加密Key 
    string _PassWordKey = "hgfedcba"; //PassWord加密Key 

    //加密URL传输的字符串
    public string EncryptQueryString(string QueryString)
    {
        return Encrypt(QueryString, _QueryStringKey);
    }

    //解密URL传输的字符
    public string DecryptQueryString(string QueryString)
    {
        return Decrypt(QueryString, _QueryStringKey);
    }

    //加密帐号口令
    public string EncryptPassWord(string PassWord)
    {
        return Encrypt(PassWord, _PassWordKey);
    }

    //解密帐号口令
    public string DecryptPassWord(string PassWord)
    {
        return Decrypt(PassWord, _PassWordKey);
    }

    // DEC 加密过程
    public string Encrypt(string pToEncrypt, string sKey)
    {
        DESCryptoServiceProvider des = new DESCryptoServiceProvider(); //把字符串放到byte数组中 

        byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);
        //byte[] inputByteArray=Encoding.Unicode.GetBytes(pToEncrypt); 

        des.Key = ASCIIEncoding.ASCII.GetBytes(sKey); //建立加密对象的密钥和偏移量 
        des.IV = ASCIIEncoding.ASCII.GetBytes(sKey); //原文使用ASCIIEncoding.ASCII方法的GetBytes方法 
        MemoryStream ms = new MemoryStream(); //使得输入密码必须输入英文文本 
        CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);

        cs.Write(inputByteArray, 0, inputByteArray.Length);
        cs.FlushFinalBlock();

        StringBuilder ret = new StringBuilder();
        foreach (byte b in ms.ToArray())
        {
            ret.AppendFormat("{0:X2}", b);
        }
        ret.ToString();
        return ret.ToString();
    }

    /// DEC 解密过程 
    public string Decrypt(string pToDecrypt, string sKey)
    {
        DESCryptoServiceProvider des = new DESCryptoServiceProvider();

        byte[] inputByteArray = new byte[pToDecrypt.Length / 2];
        for (int x = 0; x < pToDecrypt.Length / 2; x++)
        {
            int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));
            inputByteArray[x] = (byte)i;
        }

        des.Key = ASCIIEncoding.ASCII.GetBytes(sKey); //建立加密对象的密钥和偏移量，此值重要，不能修改 
        des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
        MemoryStream ms = new MemoryStream();
        CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);

        cs.Write(inputByteArray, 0, inputByteArray.Length);
        cs.FlushFinalBlock();

        StringBuilder ret = new StringBuilder(); //建立StringBuild对象，CreateDecrypt使用的是流对象，必须把解密后的文本变成流对象 

        return System.Text.Encoding.Default.GetString(ms.ToArray());
    }

    /// 检查己加密的字符串是否与原文相同 
    public bool ValidateString(string EnString, string FoString, int Mode)
    {
        switch (Mode)
        {
            default:
            case 1:
                if (Decrypt(EnString, _QueryStringKey) == FoString.ToString())
                {
                    return true;
                }
                else
                {
                    return false;
                }
            case 2:
                if (Decrypt(EnString, _PassWordKey) == FoString.ToString())
                {
                    return true;
                }
                else
                {
                    return false;
                }
        }
    }
}
